Process of improving salad oils



Patented Dec. 16, 1941 UNITED .STATES PATENT OFFICE PROCESS OF IMPROVING SALAD OILS Eddy W. Eckcy and Edwin S. Lutton, Wyoming,

Ohi

o, assignors to The Procter & Gamble Company, Ivorydale, Ohio, a corporation of Ohio No Drawing. Application October 14, 1938,

Serial No. 235,101

18 Claims.

This invention relates to a process of improving salad oils.

An object of our invention is to retard the deposition of stearine at low temperature from salad oils such as are used in the preparation of salad dressings, and especially from so-called winter oils such as winterized cottonseed oil or cottonseed oil whose stearine has been largely removed by fractional crystallization.

Another object of our invention is to lengthen the so-called cold test of salad oils.

Another object of our invention is to provide a salad oil from which a mayonnaise emulsion having improved stability at low temperature may be prepared.

As used herein the term "stearine" designates the higher melting fraction of the oil which sepacrystallized and subsequently removed by filtrarates on cooling. The term does not infer, howi ever, that the high melting fraction consists entirely or even mainly of the glycerides of stearic acid.

The term salad oil" means any refined liquid vegetable oil which does not deposit stearine on prolonged standing at temperatures in the ordinary range of room temperatures.

The term low temperature" designates the lower range of normal atmospheric temperature, not below the clouding point of the salad oil, at which the oil will deposit stearine on standing.

The clouding point of an oil is the temperature at which the first permanent cloud shows in the body of a sample of the dry oil and is determined in accordance with a standard test known as the "cloud test described in detail in the Omcial Methods of Analysis of the American Oil Chemists Society.

The degree of stability of the salad oil against the deposition of stearine at low temperature or the degree of retardation of crystallization is determined by means of a test known as the "cold test. The term cold test as employed herein designates the length of time in hours a four ounce sample of the oil contained in a four ounce oil sample bottle may be submerged in an icewater bath at C. before the oil becomes cloudy due to the deposition of stearine (see the Oilicial Methods of Analysis of the American Oil Chemists Society).

It is a well known fact that those who employ salad oils for table use dislike those oils which will deposit stearine or become cloudy at ordinary room temperatures which it must be remembered, sometimes drop to as low as 40 to 50 F. for limited periods during the winter season. The natu- 5 the cold test or the degree of stability of the oil tion, gravity separation, or pressing. The "mother liquor" from such crystallization then contains relatively little stearine and constitutes a satisfactory salad oil and will stand exposure at moderately low temperatures such as 50' F. for many hours or days without separation of stearine but, of course, at a sufliciently low temperature separation of stearine may still occur. Such salad oils as ordinarily prepared for commercial use as a general rule deposit stearine more readily than natural salad oils such as olive oil or corn oil and for this reason the use of winterized oils such as winter cottonseed oil is mainly confined to purposes where resistance to extremely low temperatures is not required.

Of course winterized oils, more comparable with olive oil or corn oil and therefore possessing an exceptionally long cold test, can be prepared by Winterizing at lower temperatures than ordinary, whereby a greater proportion of stearine is separated and a mother liquor or liquid fraction (winterized oil) is obtained having an unusually long cold test and a resistance to unusually low temperatures without separation of stearine. The making of products in accordance with this procedure is uneconomical and, in fact, impractical in most instances. It should be remembered that the relative degree of stability of salad oils is shown by the results of cold tests conducted thereon, the oil showing the longer cold test being capable of withstanding for longer periods low temperatures at which crystallization will ultimately take place.

-. In mayonnaise manufacture also the relative degree of stability of salad 'oils against deposition of its stearine is an important factor. The

ease with which mayonnaise emulsions prepared from such vegetable salad'oils are broken by low storage temperatures is closely associated with temperatures of storage. From this standpoint also, therefore, it is important that the salad oil employed be capable of withstanding low temperatures for long periods without deposition of its stearine.

We have discovered a method for retarding such deposition of stearine from vegetable salad oils at low temperatures which comprises dissolving in the oil a fatty acid ester derived from a mixture of fatty acids, including a proportion of higher saturated fatty acid, and a hydroxy substance selected from any one of the following groups.

A. Polyhydric alcohols containing more than three hydroxyl groups.

B. Derivatives of polyhydric alcohols having at least two hydroxyl groups, said derivatives containing more than three hydroxyl groups.

C. Aliphatic hydroxy carboxylic acids having at least one hydroxyl group for each four carbon atoms in the aliphatic chain.

Examples of compounds which may be employed in the practice of our invention are as follows, it being understood that where frmulas are given R represents the acyl radical of the fatty acid,

Products coming within the scope of group A:

1. The completely esterified ester prepared from sorbitol and the following mixture of fatty acids: two parts palm oil fatty acids, 1 part coconut oil fatty acids, 1 part fatty acids derived from substantially completely hydrogenated rapeseed oil.

2. Sorbitol partially stearic acid.

3. Sorbitol partially esterified with the fatty acids of cottonseed oil hydrogenated to about 65 iodine value.

Other polyhydric alcohols having more than three hydroxyl groups such as mannitol, dulcitol, erythritol, etc., may be employed in the place of sorbitol.

Products coming within the scope of group B:

1. The completely esterified ester made from di-glycerol and the fatty acid mixture consisting of approximately equal parts of commercial stearic acid, commercial oleic acid and the acids derived from substantially completely hydrogenated rapeseed oil. I

2. Polyglycerol completely esterified with a mixture of equal parts of commercial stearic acid and commercial oleic acid.

3. Polyglycerol completely esterified with the mixture of fatty acids consisting of two parts palm oil fatty acids, one part coconut oil fatty acids, and one part fatty acids derived from substantially completely hydrogenated rapeseed oil.

4. An ester prepared by esterifying about three fourths of the hydroxyl groups of polyglycerol with a mixture of fatty acids derived from substantially completely hydrogenated cottonseed oil and the remaining one fourth with butyric acid.

5. Glycol tartrate completely esterified with a mixture of four parts commercial stearic acid and one part oleic acid.

0 0 O-CHr-CHzOR LHOR (SHOE OO-CHr-CBzOR esterified with commercial 6. The carbonate of the monoglyceride prepared from glycerin and commercial stearic acid.

CH:0R

HOH

Hr-OR 7. The carbonate of the diglyceride prepared from glycerin and commercial stearic acid.

CH:OR

rr-o-a Hr-O c=0 cm-o 11-0-11 (EHr-OR 8. The ester of diglyceride (prepared from glycerin and a mixture of myristic acid, castor oil fatty acids, and commercial stearic acid) and malic acid.

COOCHr-CH-CH:

H1 l HOH I R OOCHa-CH-CH:

9. Diglyceryl sebacate esterified with a mixture of commercial stearic acid and oleic acid.

doocm-ou-cm OOCHr-dH-CH! 10. Triglyceryl citrate esterified with a mixture of commercial stearic acid, myristic acid, and castor oil fatty acids.

COO-CHr-CH-CH:

- C 0 O-GHr-CH-CH:

C 0 0-0 Hr-CH-C H2 trio-R ino-a Hr-COOH required to accomplish eflectiveiy a-suflicient re- 2. Gluconic acid substantially completely esterifled with commercial stearic acid.

8. Mucic acid completely esterifled with a mixture of fatty acids derived from tallow.

Similar fatty acid esters of other hydroxy carboxylic acids such as malic, xyionic, mannonic, arabonic, and rhamnonic also come within this group.

1 It will be noted from the above that partially esterifled products as well as'completely esterifled products are usable in the practice of our invention. However, we have found that in general the completely esterifled products are sometardation of crystallization. The amount of course varies depending on the type of salad oil being treated and on the type of agent being employed. In general, lessthan one per cent will be sufllcient and 'in the course of experimental work it has been found that an amount what more effective and therefore are preferred for retarding stearine deposition in accordance with our discovery.

Furthermore, although we have found that the fatty acid mixture employed for esteriflcatio'n of the hydroxy substance should contain a proportion of higher saturated fatty acid, i. e., containing at least eight carbon atoms, preferably eight to twenty-two carbon atoms, per molecule, such as lauric, myristic, palmitic, stearic, etc., it should be borne in mind that too high a proportion may actually be detrimental to the oil at least from the standpoint of its suitability for table use. For example, an agent which is too high melting or too insoluble in the oil may in fact retard, to some degree, the deposition of stearine from the oil to which it is added and therefore effect some improvement in the stability of mayonnaise emulsions prepared from the oil, but because of its high melting characteristics or its insolubility in the oil, may precipitate from the oil itself, thereby causing an undesirable cloud and making the oil less desirable for table use. Because of diiferences in character in the large 'variety of compounds which may be employed as retarding agents in the practice of our invention, and because of the differences in the degree of retardation required in salad oils, it is impossible to state deflnitely, without imposing undue limitations, the melting point or the percentage of saturated fatty acid permissible in the compositions. A great number of compounds which have been successfully employed possess melting points in the range of 80 to 130 F. but of course this range is given merely as a guide in practicing the invention and is not to be construed as a' limitation of scope. Therefore when the oil is to be employed for table use, it is desirable that in the range from about 0.02% to about 0.25%

of the more active agents is ample to effect the desired degree of retardation.

In the course of our work, we have found that although the use of a relatively large amount of some of the retarding agents in a salad oil may effect material stabilization against stearine deposition, difliculties may be encountered in preparing a mayonnaise of satisfactory stability from oils so treated. This effect is most noticeable when partially esterified products are employed as agents for retarding stearine deposition. As is well known, such compounds are emulsifying agents-for oil-water emulsions and therefore materially affect the interfacial tension of the oil. One would expect, therefore, that emulsions, such as mayonnaise emulsions, made from oils containing such retarding agents would be especially stable against separation. Such, however, is not true. Retarding agents possessing the ability to modify the interfacial tension of oils and of particular advantage in the preparation of certain types of emulsions, have what might be termed an antagonistic effect toward the emulsifying action of the egg employed in mayonnaise production with a resulting positive adverse effect on emulslflcation and emulsions which may thereby be produced. In the practice of our invention, therefore, it is important that any change in the interfacial tension of the salad oil effected by the addition of the retarding agent be insuflicient to adversely affect the stability of mayonnaise emulsions produced therefrom. Since the retarding agents which possess unesterifled hydroxyl groups are more,

active as interfacial tension modifiers, (the greater the number of unesterifled hydroxyl groups for any given type of ester the greater its activity in this respect), these substances must 7 be used with particular care, especially if the sufficient retarding agent be employed to retard stearine deposition at low temperature and that solubility and melting point of the agent be such that precipitation of same from the salad oil will not take place at any temperature to which the oil may be subjected for prolonged periods. If the oil is to find exclusive use in mayonnaise manufacture, slight cloudiness at low temperature caused by precipitation of retarding agent resulting, for example, from the use of too high a proportion of a, high melting compound is not a major concern since, in spite of its slight cloudiness at low temperature, the oil may in fact produce a mayonnaise emulsion of superior stability.

As indicated by product 4 of group B above, the desired solubility and/or melting point of the ester may be adjusted by employing a lower molecular weight aliphatic carboxylic acid, such as butyric acid,'along with the higher saturated fatty acid in preparing the esters of the hydroxy substances. Other low molecular weight acids such as acetic and valeric may also be employed.

salad oil is apt .to find use in the manufacture of mayonnaise emulsions. I

Therefore, although we have given above by way of example numerical percentages when speaking of the amount of retarding agent to be used in the practice of our invention, it should be borne in mind that broadly speaking the amount of retarding agent is chosen in relation to the ratio of its esterified to its unesterifled hydroxy groups so that substantial retardation Only a small amount of retarding agent is of crystallization of the salad oil is effected at low temperatures without material change of the interfacial tension of the oil. The specific amounts given above are insuflicient to materially affect the interfacial tension of the salad oil.

The following examples willillustrate in what manner our invention may be practiced, it being understood, of course, that the specific limitations are by way of example only and that the scope of the invention is not to be limited thereto but rather to the breadth of the appended claims.

In connection with working our invention as is illustrated by the following examples, solution of the retarding agent in effected in a number of ways known to those versed in the art, e. g., combining the constituents in liquid condition, adding the retarding the salad oil may be agent in solid form to the oil which has been slightly heated, etc. The resulting compound is merely a physical mixture and in no case do we effect a chemical reaction between the constituents.

Example 1.-In a winterized cottonseed oil having a cold test of six and one half hours was dissolved 0.02% of a polyglycerol completely esteriiled with a mixture of fatty acids consisting of 2 parts palm oil fatty acids, 1 part coconut oil fatty acids and 1 part fatty acids obtained from substantially completely hydrogenated rapeseed oil. A cold test of about 30 hours on the thus treated material was noted.

Example 2.In a sample of winterized cottonseed oil having a cold test of 12 hours was dissolved 0.1% of sorbitol completely esterifled with a mixture of fatty acids consisting of 2 parts palm oil fatty acids, 1 part coconut oil fatty acids and 1 part fatty acids derived from substantially completely hydrogenated rapeseed oil. The treated oil had a cold test of about 22 hours.

Example 3.--In a sample of winterized cottonseed oil having a cold test of 8 hours was dissolved 0.02 per cent of an ester prepared by esterifying about three fourths of the hydroxyl groups of polyglycerol with the mixture of fatty acids derived from substantially completely hydrogenated cottonseed oil and the remaining one fourth with butyric acid. The treated oil had a cold test of about 30 hours.

Example 4.Slution of 0.1% of the ester prepared by' esterifying the reaction product of glycerin and sebacic acid with a mixture of commercial stearic acid and oleic acid in a winterized cotton seed oil having a cold test of about 18 hours, increased the cold test to 47 hours.

Example 5.Solution of 0.1% of the retarding agent employed in Example 1 in a sample of refined soybean oil, lengthened the cold test ofthe oil from 6% hours to about 67 hours.

Example 6.Solution of 0.1% of the retarding agent employed in Examples 1 and in a sample of olive oil lengthened the cold test of the oil from about 22 hours to' over 72 hours.

The above procedure is applicable also to other salad oils such as corn oil for example.

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. The process of retarding the deposition of stearine from salad oil at low temperature comprising dissolving in saladfoilyithout chemical reaction a small-amount off an ester of fatty acids comprising a proportion of higher saturated fatty acid and a substance selected from the group of hydroxy substances consisting of polyhydric alcohols containing more than three hydroxyl groups, organic derivatives of polyhydric alcohols having at least two hydroxyl groups, said derivatives containing more than three hydroxyl groups, and aliphatic hydroxy carboxylic acids having at least one hydroxyl group for each four carbon atoms in the aliphatic chain.

2. The process of retarding the deposition of stearine from salad oil at low temperature comprising dissolving in salad oil without chemical reaction less than one per cent of an ester of a mixture of fatty acids comprising a substantial proportion of higher saturated fatty acid and a substance selected from the group of hydroxy substances consisting of polyhydric alcohols containing more than three hydroxyl groups, or-. ganic derivatives of polyhydric alcohols having at least two hydroxyl groups, said derivatives containing more than three hydroxyl groups, and aliphatic hydroxy carboxylic acids having at least one hydroxyl group for each four carbon atoms in the aliphatic chain.

3. The process of retarding the deposition of stearine from salad oil at low temperature comprising dissolving in salad oil without chemical reaction less than one per cent of an ester of a mixture of fatty acids comprising a substantial proportion of higher saturated fatty acid and a substance selected from the group of hydroxy substances consisting of polyhydric alcohols containing more than three hydroxyl groups, or-

ganic derivatives of polyhydric alcohols having at least two hydroxyl groups, said derivatives containing more than three hydroxyl groups, and aliphatic hydroxy carboxylic acids having at least one hydroxyl group for each four carbon atoms in the aliphatic chain, said percentage being so chosen in relation to the ratio of the esterifled to the unesterifled hydroxyl groups of the ester that substantial retardation of crystallization of the salad oil is effected at low temperature without material change of the interfacial tension of the oil.

4. The process of retarding the deposition of stearine from salad oil at low temperature comprising dissolving in salad oil without chemical reaction from about 0.02 to about 0.25 per cent of an ester of a mixture of fatty acids comprising a substantial proportion of higher saturated fatty acid, and a substance selected from the group of hydroxy substances consisting of polyhydric alcohols containing more than three hydroxyl groups, organic derivatives of polyhydric alcohols having at least two hydroxyl groups, said derivatives containing more than three hydroxyl groups, and aliphatic hydroxy carboxylic acids having at least one hydroxyl group for each four carbon atoms in the aliphatic chain.

5. The process of retarding the deposition of stearine from salad oil at low temperature comprising dissolving in salad oil without chemical reaction a small amount of a completely esterified fatty acid ester derived from a mixture of fatty acids containing a substantial proportion of higher saturated fatty acid, and a substance selected from the group of hydroxy substances consisting of polyhydric alcohols containing more than three hydroxyl groups, organic derivatives of polyhydric alcohols having at least two hydroxyl groups, said derivatives containing more than three hydroxyl groups, and aliphatic hydroxy carboxylic acids having at least one hydroxyl group for each four carbon atoms in the aliphatic chain.

6. The process of retarding the deposition of stearine from salad oil at low temperature comprising dissolving in salad oil without chemical reaction less than one per cent of a polyhydric alcohol containing more than three hydroxyl groups completely esterifled to form a mixed ester in which the combined fatty acid consists partially of higher saturated fatty acid.

'7. The process of retarding the deposition of stearine from salad oil at low temperature comprising dissolving in salad 011 without chemical reaction and incorporating therewith less than one per cent of polyglycerol completely esterified to form a mixed ester in which the combined fatty acid consists partially of higher saturated fatty acid.

8. The process of retarding the deposition of stearine from salad oil at low temperature comprising dissolving in salad oil without chemical reaction less than one per cent of a fatty acid ester derived from a mixture of fatty acids containing a predominant proportion of higher saturated fatty acid and a derivative of glycerin in which derivative'at least two molecules of glycerin are combined through an ether linkage, said percentage being so chosen in relation to the ratio of the esterified to the unesterifled hydroxyl groups of the ester that substantial retardation of crystallization of the salad oil is effected at low temperature without material change of the interfacial tension of the oil.

9. The process of retarding the deposition of stearine from salad oil at low temperature comprising dissolving in salad oil less than one per cent of a completely esterified ester derived from a mixture of higher fatty acids consisting partially of a higher saturated fatty acid and a derivative of glycerin in which derivative at least two glycerin molecules are bridged by an organic acid containing at least two carboxyl groups.

10. The process of retarding the deposition of stearine from winterized cottonseed oil at low temperature comprising dissolving in the oil without chemical reaction less than one per cent of an ester of fatty acids comprising a predominant proportion of higher saturated fatty acid and a substance selected from the group of hydroxy substances consisting of polyhydric alcohols containing more than three hydroxyl groups, derivatives of polyhydric alcohols having at least two hydroxyl groups, said derivatives containing more than three hydroxyl groups and aliphatic hydroxy carboxylic acids having at least one hydroxyl group for each four carbon atoms in the aliphatic chain, said percentage being so chosen in relation to the ratio of the esterified to the unesterified hydroxyl groups of the ester that substantial retardation of crystallization of the oil is effected at low temperature without material change of the interfacial tension of the oil.

11. The process of retarding the deposition of stearine from winterized cottonseed oil at low temperature comprising dissolving in the oil without chemical reaction less than one per cent of a fatty acid ester derived from a mixture of fatty acids containing predominant proportion of higher saturated fatty acid and a derivative of glycerin, in which derivative at least two molecules of glycerin are combined through an ether linkage, said percentage being so chosen in relation to the ratio of the esterified to the unesterified hydroxyl groups of the ester that substantial retardation of crystallization of the oil is effected at low temperature without material change of the interfacial tension of the oil.

12. The process of retarding the deposition of stearine from winterized cottonseed oil at low temperature comprising adding to the oil and incorporating therewith without chemical reaction less than one per cent of polyglycerol completely esterified with a mixture of higher fatty acids consisting partially of a higher saturated fatty acid, said ester being substantially completely soluble in the oil at the said low temperature.

13. The process of retarding the deposition of stearine from salad oil at low temperature, comprising dissolving in salad oil without chemical reaction an ester of a mixture of fatty acids comprising a substantial proportion of higher saturated fatty acid and a substance selected from the group of hydroxy substances consisting of polyhydric alcohols containing more than three hydroxyl groups, organic derivatives of polyhy-' dric alcohols having at least two hydroxyl groups, said derivatives containing more than three hydroxyl groups, and aliphatic hydroxy carboxylic acids having at least one hydroxyl group for each four carbons in the aliphatic chain, the said ester having a melting point within the range of F. to F. and being employed in amount willcient to retard the deposition of stearine from salad oil but less than one per cent and less than that amount which will exceed the solubility of said ester in said salad oil at said low temperature.

14. The process of retarding the deposition of stearine from salad oil at low temperature, comprising dissolving in salad oil without chemical reaction, and incorporating therewith, polyglycerol completely esterified to form a mixed ester in which the combined fatty acid consists predominantly of higher saturated fatty acid, the said ester being employed in amount sufllcient to retard the deposition of stearine from the salad oil but less than one per cent and less than'that amount which will exceed the solubility of said ester in said salad oil at said low temperature.

15. The process of retarding the deposition of stearine from winterized cottonseed oil at low temperature, comprising adding to the oil and incorporating therewith without chemical reaction less than one per cent of polyglycerol completely esterified with a mixture of higher fatty acids consisting predominantly of higher saturated fatty acids, the said ester being substantially completely soluble in the oil at the said low temperature.

16. The process of retarding the deposition of stearine from salad oil at low temperature, comprising dissolving in salad oil without chemical reaction less than one per cent of a completely esterified fatty acid ester derived from a mixture of fatty acids containing a substantial proportion of stearic acid and a substance selected from the group of hydroxy substances consisting of polyhydric alcohols containing more than three hydroxyl groups, organic derivatives of polyhydric alcohols having at least two hydroxyl groups, said derivatives containing more than three hydroxyl groups, and aliphatic hydroxy carboxylic acids having at least one hydroxyl group for each four carbonsin the aliphatic chain, the said ester having a melting point within the range of 80 F. to 130 F. and being employed in amount sufilcient to retard the deposition of stearine from salad oil but less than one per cent and less than that amount which will exceed the solubility of said ester in said salad oil at said low temperature.

17. The process of retarding the deposition of stearine from salad oil at low temperature, comprising dissolving in salad oil, without chemical reaction, less than one per cent of a fatty acid ester derived from a mixture of fatty acids containing a predominant proportion of higher saturated fatty acid, and a derivative of glycerin, in which derivative at least two molecules of glycerin are combined through ester linkages, said percentage being so chosen in relation to the ratio of the esterified to the unesterified hydroxyl groups of the ester that substantial retardation of crystallization of the salad oil is effected at low temperature without material change of the interfacial tension of the oil.

18. The process of retarding the deposition of stearine from winterized cottonseed oil at. low temperature, comprising dissolving in winterized cottonseed oil, without chemical. reaction, less than. one per cerit of a fatty acid ester derived from a mixture of iatty acids containing a predominant proportion of higher saturated fatty acid, and a derivative of glycerine, in which derivative at least two molecules 01 giycerine are combined through ester linkages, said percentage being so chosen in relation to the ratio ot-the esteriiied to the unesterifled hydroxyl groups of the ester that substantial retardation oi crystallization of the winterized cottonseed oil is eflected at low temperature without material change of the interiaciai tension of the oil.

' EDDY w. ECKEY. EDWIN s. LU'I'ION. 

